Spiral valves are found in

The number of teeth that grow only once in a human's lifetime is .......

The structure of a tooth is given below. What are $P$ and $Q$?

Explain the terms thecodont and diphyodont.

The vermiform appendix is a part of which system?

Kupffer cells of the liver help in . . . . . . .
$i$. Detoxification
$ii$. Synthesis of vitamin $A, D, K$ and $B_{12}$
$iii$. Emulsification of fats
$iv$. Deamination of amino acids
$v$. Phagocytosis